1. Field of the Invention
The present invention relates to systems, devices and methods for delivering therapeutic fluids to a patient, and more particularly, to portable infusion devices (e.g., pumps). Some embodiments of the invention relate to infusion devices, which are adherable directly to a patient's skin. Some embodiments of the present invention are directed to a “well-arrangement”, which couples a fluid delivery tube emerging from a reservoir in an infusion device to a cannula for subcutaneous insertion into the body of a patient.
2. Background of the Invention
Conventional subcutaneous delivery devices of therapeutic fluid into the body of a patient are also known as ambulatory “pager-like” portable infusion pumps that are used mainly for continuous insulin delivery. Typically, these pager-like pumps are attached to a belt which is secured to the patient. A long delivery tube is then connected to the reservoir within the device and also to a subcutaneous cannula of an infusion set.
Conventional ambulatory infusion pumps were developed for continuously delivering drugs to a patient. These ambulatory infusion pumps often contain a reservoir and a long tube for delivering the drug to a subcutaneous cannula of the infusion set. The cannula is often inserted together with a sharp penetrating member. Examples of such infusion pumps are disclosed in U.S. Pat. Nos. 6,423,035 and 8,872,200.
Additional examples of conventional fluid infusion devices are disclosed in the following patents. U.S. Pat. No. 6,093,172 to Funderburk et al. and U.S. Pat. No. 6,830,562 to Mogensen et al. disclose an injector device that includes a spring-loaded plunger for an automatic subcutaneous placement of an infusion set. U.S. Pat. No. 6,699,218 to Flaherty et al. discloses a skin-adherable device for delivering fluid to a patient that includes a housing with a reservoir chamber. The chamber is in fluid communication with a dispenser for dispensing the fluid from the reservoir in finite amounts to an exit port assembly from which liquid medication exits and enters the body of the patient. The device in the Flaherty patent also allows for an automatic cannula insertion. Such insertion is possible through the use of relatively heavy and bulky components which substantially extend device dimensions.
After insertion, the cannula is steadily retained in its subcutaneous location regardless of the movements of the body of the patient or relative movements between the housing of the pump and the cannula. This causes various difficulties with skin-adherable infusion devices.
Other problems with current infusion devices include reluctance of some patients to pierce their own skin with a needle. Such patients typically use automatic insertion devices to address this problem. Yet other patients prefer a manual insertion process.
Some disadvantages of conventional devices and methods for fluid delivery to a patient are summarized below:                Long tubing: in typical pager-like insulin pumps, the long fluid delivery tube tends to fold, kink, rupture and/or disconnect. Moreover, such tubes do not allow discreetness and restrict activity of the patient.        Rigid cannula connection: in conventional skin-adherable pumps, the cannula is rigidly connected to the housing, thus, abrupt movements of the body of the patient can cause patient discomfort, detachment of the cannula from the patient and/or its disconnection from the housing of the device.        Insertion mechanisms: some conventional insertion mechanisms are incorporated within the device housing. Such devices are relatively heavy and bulky and are carried by the user for the entire operating period (usually 3-4 days).        One length cannula: pre-mounted cannulas in some current infusion devices have only one predetermined length.        Fixed insertion angle: in some conventional pager-like devices, the patient can insert the infusion set only at a single predetermined penetration angle, usually 30°, 45° or 90°.        
Thus, it is desirable to provide a system, device and/or method to address the above-noted problems of conventional fluid delivery devices. In particular, it is desirable to provide a subcutaneous cannula insertion that allows the patient maximal flexibility in choosing cannula length, insertion modes and penetration angles.